基于微透镜阵列的激光光束整形技术研究

发布时间：2018-06-01 09:25

本文选题：光束整形 + 微透镜阵列　；参考：《南京理工大学》2015年硕士论文

【摘要】：在材料处理、医学手术、半导体制造、激光核聚变及全息术等激光应用领域,激光光束的能量分布不均匀特性限制了其应用,需将高斯光束整形成能量均匀分布的平顶激光束。目前国内大多采用非球面透镜组、二元光学元件或空间光调制器构成光束整形均化装置,而鲜有对以微透镜阵列(Microlens array, MLA)作为均化元件的激光均化器研究。微透镜阵列均化器具有结构简单、制造成本低、对入射光束变化不敏感等优点,所以研究基于微透镜阵列的激光光束均化技术有很大的工程意义和应用价值。本文主要研究了微透镜阵列为主要元件组成的衍射型和成像型两种结构光束均化器。首先以标量衍射理论为基础,详细推导了两种结构均化器的目标面理论光场分布的数学表达式。根据几何光学成像公式得到目标面光斑大小与系统参数的关系。然后以菲涅尔数评价均化器中衍射效应,通过MATLAB软件仿真菲涅尔数变化对均化光斑的影响。用算子光学方法得到了两种微透镜阵列均化器的等效模型。最后,分析了准直激光器作为光源时均化面的干涉效应,对于高相干光源均化光光斑不可避免的出现高对比度的干涉点阵图。本文构建了衍射型与成像型微透镜阵列均化试验系统,计算测量结果并与论文推导的理论结果相比较。实验结果证明了文中所建立的微透镜阵列均化器模型正确有效。说明了微透镜阵列作为激光光束均化器主要元件的可行性和高效性。
[Abstract]:In the fields of material processing, medical surgery, semiconductor manufacturing, laser fusion and holography, the nonuniformity of laser beam energy distribution limits its application. It is necessary to shape the Gao Si beam into a flat-top laser beam with uniform energy distribution. At present, most of our country use aspheric lens group, binary optical element or spatial light modulator to form beam shaping and homogenizing device, but there are few researches on laser equalizer with microlens array (MLA) as homogenization element. Microlens array homogenizer has the advantages of simple structure, low manufacturing cost and insensitivity to the change of incident beam, so it is of great engineering significance and application value to study laser beam equalization technology based on microlens array. In this paper, the diffractive and imaging beam equalizers composed of microlens arrays are studied. Firstly, based on the scalar diffraction theory, the mathematical expressions of the theoretical light field distribution on the target surface of two kinds of structural equalizers are derived in detail. According to the geometric optical imaging formula, the relationship between the target surface spot size and the system parameters is obtained. Then the diffraction effect in the equalizer is evaluated by Fresnel number, and the influence of Fresnel number change on the equalization spot is simulated by MATLAB software. The equivalent models of two kinds of microlens array equalizers are obtained by using operator optics method. Finally, the interference effect of collimation laser as a light source is analyzed, and a high contrast interference dot matrix is inevitable to homogenize the light spot of high coherent light source. In this paper, a diffractive and imaging microlens array homogenization test system is constructed. The measured results are compared with the theoretical results derived in this paper. The experimental results show that the model of microlens array equalizer is correct and effective. The feasibility and efficiency of microlens array as the main component of laser beam equalizer are explained.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TN24

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